Mako Gamma Control

As posted on XDA
http://forum.xda-developers.com/showpost.php?p=36956045&postcount=5
LG Mako gamma control - add mirror interface while leaving
faux's interface in place, respecting his rollover char checksum.

Mirror interface should be a little easier for humans to work
with from scripting (int checksum that doesn't roll over).

Added a couple validation checks to both interfaces before allowing
values to be stored. This will add some safety for scripting or rouge
apps that may have a bug.
-Only allow gamma amp 0 and 1 values up to 31.
-Since we are pushing to a char data type, make sure nothing is over
255.

Changed dsi_cmd_desc struct name so it can be shared between
both interfaces.

Added to sysfs:
/sys/devices/platform/mipi_lgit.1537/kgamma_red
/sys/devices/platform/mipi_lgit.1537/kgamma_green
/sys/devices/platform/mipi_lgit.1537/kgamma_blue

Example:
echo "383 114 21 118 0 0 0 80 48 2" >
/sys/devices/platform/mipi_lgit.1537/kgamma_red

echo "383 114 21 118 0 0 0 80 48 2" >
/sys/devices/platform/mipi_lgit.1537/kgamma_green

echo "383 114 21 118 0 0 0 80 48 2" >
/sys/devices/platform/mipi_lgit.1537/kgamma_blue

First digit is a checksum (sum of all the other 9 numbers)
Gamma Amp 0 = value 6
Gamma Amp 1 = value 7

Show the current settings with proper checksum:
cat /sys/devices/platform/mipi_lgit.1537/kgamma_red
cat /sys/devices/platform/mipi_lgit.1537/kgamma_green
cat /sys/devices/platform/mipi_lgit.1537/kgamma_blue
Gamma Control - added refresh_screen sysfs attribute that has nothing to
do with setting values. This should only be called by apps or scripts
while adjusting colors "live" with the motley or faux interface and not
implemented on startup via init.d or apps since it will compete with the
normal power on process.

echo 1 > /sys/devices/platform/mipi_lgit.1537/refresh_screen
mako LCD: keep RGB custom colors alive after screen off/on

When the back-light turns back on, reset the RGB values set in
sysfs (/sys/devices/platform/kcal_ctrl.0/kcal)
Fix warning in display file

Using GCC 4.7.0, the following warning occurred: warning: initialization from incompatible pointer type

Let's stick the the regular implementation for the store function.
Fixing a mistake